Apparatus for controlling zone hardening



I 1942- F. s. DENNEEN ETAL 2,292,209-

APPARATUS FOR CONTROLLING ZONE HARDENING Filed Aug. 2, 1940 substantially on line 22 of Fig. 1. section similar to Fig. 2 showing a modification Fatentedl Aug. 4, 1942 I TATES iii i ilfifi 2,292,2i99 APPARATUS FOR oon'raomnvo zone nARpENiNo Francis S. Denneen, Cleveland, William C. Dunn,

Shaker Heights, and Courtney N. Mitchell Strongsville, Ohio, asslgnors to The Ohio Crankshaft Company, Cleveland, @hio, a corporation of Ohio The present application as a continuation in part of our copending application Serial No. 718,003, now Patent No. 2,213,241, is directed principally to that part of the invention which provides an inductorso formed as to control both the distribution of heating in the article being treated and the distribution of quenching fluid so as to regulate and modify the degree of hardness to correspond with prescribed conditions.

In the heat treatment of articles, frequently it is desired that a certain part be provided with a higher degree of hardness than an adjacent part, or that the hard surface zone of one part have a greater depth than another zone, or part of a zone on the same article. In some cases, a part is left entirely unhardened between otherwise adjacent hardened zones. All of these conditions can be attained by the correct form and proportions of the inductor employed and by the correct application of the quenching medium when heating is accomplished by current induced in the article to be treated.

With these conditions in view, this invention has, as its chief object, the provision of apparatus adapted to control the distribution of heating in an article to be hardened. A further object is the provision of means to regulate the depth of various parts of heated surface zones. An additional object is to provide mechanism adapted to regulate the distribution of quenching fluid over a surface of an article to be hardened. A still further object is to provide means for hardening zones'in intersecting surfaces.

With these ,and other objects in view, this invention then consists of the apparatus shown in the accompanying drawing and described in this specification, together with the method of procedure in using this and similar apparatus.

In the said drawing Fig. 1 is an elevation of the preferred form of our improved apparatus on line Il of Fig. 2. Fig. 2 is a vertical section Fig. 3 is a of our apparatus. Fig. 4 is a section of a further modification of our apparatus, also similar to Fig. 2.

In Figs. 1 and 2, the inductor is substantially in the form of a ring and, when required, is formed in two interconnected parts which can be opened to facilitate placing the inductor around a journal of a crankshaft or similar article, such as crank pin I4 when this pin is located between two crank arms.

12 illairns.

is of a general ellipsoidal or other curved form varying in distance from the cylindrical elements of the shaft to provide a greater air gap at the central part of the cylinder than at its ends. This face is provided with circumferentially ex tending grooves such as IE5, l6 and I! which control the distribution of current across this face and the resulting distribution of heat along the surface of the shaft. By suitably forming the side portions such as it of this inductor, the faces of the flanges at the ends of the hearing such as 26 are heated to hardening temperature as well as the cylindrical portions directly under the inductor. The inwardly projecting rings 22, 23, 2t and 25 which may be of various widths and sectional form produce heated zones substantially as shown by the scalloped broken lines at 26 and 2?. By giving the inductor a reciprocating movement axially of the bearing during the heating period, variations in the depths of the zones .may be eliminated or reduced providing a substantially uniform depth of hardened zone as indicated at 2B in Fig. 4. By reducing the total width of the inductor and modifying the form of its side face it, the depth of the hardened zone may be reduced gradually as it approaches the fillets at 29.

For the purpose of quenching the heated surfaces of shaft it, suitable quenching mediums such as brines, caustic solutions, oil, water or gases are employed. These are conducted thru the jacket space 36 of the inductor to reduce its temperature and from there they are projected onto the heated surface of the shaft thru passages 32 which ordinarily discharge thru the grooves it, it and Ill, but other passages such as 33 are also employed traversing the rings 22, 23, 2d and 25, thus providing a more complete distribu tion of the coolant and a more uniform quenching effect. As foreign particles or undissolved salts or hydroxides may obstruct the flow of the quenchingfiuid thru passages 32 and 33, the strainer 34; is provided to remove such particles as may be suspended'in the cooling liquid. A valve 3d for controlling the delivery of coolant to the jacket space 36 is located in the pipe 35. Air under pressure from the pipe 36 is admitted to the jacket by means of valve 31 to clear the jacket of residual coolant after the cooling interval to prevent further flow or dripping during the subsequent heating interval in which the hardened surface zone is tempered by again supplying current to the inductor.

In Fig. 3 the alternate rings and grooves have The face of this inductor adjacent to the shaft 55 forms somewhat different from those shown in Figs. 1 and 2. In this flgure the central rings 4. and ll have their faces substantially parallel with shaft 42 but spaced farther therefrom than the end rings 43 and ll and are of varying widths and cross sections. Passages, such as 45 for quenching fluid enter grooves such as it and 41 from which this quenching fluid is distributed onto the surface of the shaft. Other quench fluid passages 49 pass through the rings. In this modification the ribs and grooves are so proportioned that the central ribs such as ll and 4| are narrower than the side ribs 43 and 44 which compensates for a tendency for a greater heating eflect in the part of the shaft opposite the central part of the inductor than in the parts of the shaft opposite the sides of this inductor. This reduction in the width of the ribs in some cases simplifies the construction of the inductor since in those cases it is not necessary to provide more than one inner bore diameter for all of the ribs. However, by reducing the width of the central ribs and at the same time increasing their inner diameter a very wide range of control of heating in the central part of the surface zone is attained. In the form shown in Fig. 4 all ribs are of the same inner diameter but are of different widths. In this form the quench passages 53 leading from the jacket space into the grooves are in the form of circumferentially extending slots rather than being in the form of a number of smaller orifices such as drilled holes indicated in Figs. 2 and 3. The supply of quenching fluid through these slots is sometimes supplemented by other passages 54 extending through the ribs as indicated. The

slots 53 are effective in preventing the inducing current from passing from one part of the inductor to another laterally, conflning it in definite circumferential paths.

It is sometimes desired to temper the hardening surface zones without supplying current to the inductor a second time. This is accomplished while the inductor is in place around the Joumal or other article by means of valve 34' which is of the three-way type. When in one position this valve delivers quenching fluid to harden the surface zone as above described and then after quenching is completed it is turned to interrupt this flow of quenching fluid and to turn on a supply of oil or other fluid from pipe 55 heated sufficiently to draw or reduce the hardness of the shaft by spraying this fluid onto the hardened areas thru the passages in the inductor.

The inductors shown in section in Figs. 2, 3 and 4 are of the general form indicated in Fig. 1 with current of suitable frequency and density supplied by leads such as 58 and 51. When it is desired to reciprocate the inductor to distribute heating as pointed out above, this is accomplished by any one of many mechanical devices such as a crank or eccentric to which rod 58 is connected. For such reciprocating movement the piping employed is sumciently flexible to permit the desired movement.

Other modes of applying the principle of our invention may be employed instead of the one explained, change being made as regards the means herein disclosed, provided those stated by any of the following claims or their equivalents be employed.

We, therefore, particularly point out and distinctly claim as our invention:

1. In apparatus for hardening a surface zone of an axially extending metallic article, an inductor comprising integral conductors connected in parallel, the conductors being adapted to extendperipheraliyaroundapartorthearticleand in spaced relationship therewith, the conductors being spaced from each other. means for supplying periodicallyvarying current to said conductors to induce heating current in the aforesaid surface zone means for relatively reciprocating the article and the inductor to distribute heating in the surface acne, and means for projecting a quenching medium through a space between adjacent conductors and onto said article to quench the surface acne.

2.Inapparatus forhardeningasurfaceaone of an axially extending metallic article, an inductor comprising parallel connected conductors, the conductors being integral with the inductor and being adapted to extend peripherally aroimd a part of said article and in spaced relationship therewith, means for supplying periodically varying current to said inductor to induce heating current in the aforesaid surface zone, means for reciprocating the article relative to the conductor to distribute heating substantially uniformly in the surface zone, and means for projecting a quenching medium through a wall of the inductor and substantially uniformly over the said surface zone.

3. In apparatus for hardening a surface zone of an article, an inductor, said inductor having a chamber serving as a quenching fluid supply reservoir, a current conducting wall of the reservoir being adapted to lie adjacent to the said surface zone, a slot being cut through the wall to divide the wall into individual conductors, the conductors being connected to carry substantial independent parallel inducing currents and being proportioned in size to distribute heating in the surface zone in accordance with a predetermined pattern, the said slot serving as a e for delivering a. sheet of quenching fluid from the aforesaid chamber of the inductor to the surface zone of the article, and means for supplying periodically varying current to the current conducting wall of the inductor.

4. In apparatus for hardening a surface zone of an article of substantially cylindrical form, a hollow inductor, said inductor having a chamber serving as a quenching fluid supply reservoir, a current conducting wall of the inductor being adapted to lie adjacent to the said surface acne. circumferential grooves being cut partly through the said wall to divide the wall into substantially parallel conductors, a bottom wall of a groove forming a part of a wall of the reservoir, a conductor at the central part of the inductor being at a greater distance from the aforesaid article than'a conductor adjacent to a side of the inductor, es spaced along the bottom of a groove to deliver quenching fluid from the reservoir to the aforesaid surface none, and means for supplying periodically varying current to the inductor. Q

5. In apparatus for hardening a surface acne of an article having a flllet, a hollow inductor having a wall Lying in spaced relationship with a surface of the article, the said inductor comprising spaced conductors on the article adiacmt side thereof, one of the conductors lying ad- Jacent to the flllet, and a flllet' adjacent portion of the last named conductor being cut away to provide an increased space between the cmductor and the flllet to reduce heating in the flllet.

6. In apparatus for hardening a surface'aone of an article, a hollow inductor having a wall lying in spaced relationship with a surface of the article, said wall comprising alternate ribs and grooves to provide a multiplicity of spaced conductors, the conductors being integral parts of the wall of the inductor, one of the conductors being smaller and at a greater distance from the surface of the article than an adjacent conductor, a multiplicity of passages extending thru the wall of the inductor, a part of the passages extending through the ribs and a part of the passages extending into the grooves, and means for delivering quenching fluid into said inductor and thru said passages to quench the surface zone of the article.

7. In apparatus for hardening a surface zone of a metallic article, an inductor adapted to lie in, spaced relationship with the surface zone, means for supplyingperiodically varying current to the inductor .to induce heating current in the surface zone, means for projecting quenching fluid through the inductor and onto said surface zone to quench the zone, and valve controlled means for delivering a scavaging fluid to the inductor to clear the inductor of residual quenching fluid.

8. In apparatus for hardening a surface zone of a metallic article, an inductor adapted to lie in spaced relationship with the surface zone, means for supplying periodically varying current to the inductor to induce heating current in the surface zone, valve controlled means for projecting quenching fluid through the inductor and onto said surface zone to quench the zone, and means for delivering a reheating fluid through the inductor and onto the surface zone to temper the zone.

9. In apparatus for hardening a surface zone of a substantially cylindrical article, a hollow inductor having a quenching fluid supply chamber and a current conducting wall,'said wall being adapted to lie in spaced relationship with the article, and serving as a wall of the chamber, peripherally extending grooves being cut in the wall to divide a part of the wall into substantially parallel conductors, said conductors being formed to lie at varying distances from the aforesaid surface zone, means for supplying pe-= riodically varying current to said conductors to induce heating current in the surface zone of the article, and valve controlled means for selectively delivering fluid to the aforesaid quenching fluid supply chamber.

10. In apparatus for regulating a distribution of heating in a surface zone of a. metallic article, an inductor having a wall lying in spaced relationship with a surface of the article, said wall comprising alternate ribs and grooves to provide a multiplicity of spaced conductors, the

conductors being integral parts of the wall of the inductor, one of the conductors being smaller and at a greater distance from the article than an adjacent conductor to reduce current in the said one conductor by increasing the ohmic resistance to the flow of current in the said one conductor and to reduce inductive effect of said reduced current in the one conductor by the greater distance of said reduced current from the article, and means for supplying periodically varying current to the inductor.

11. In apparatus for regulating a distribution of heating in a surface zone of a metallic article, an inductor having a current conducting wall, said wall comprising a central part and a lateral part, a side of the wall lying in spaced relationship with a surface zone of the article, said wall comprising alternate ribs and grooves on its article adjacent side to provide a multiplicity of spaced conductors, the conductors being integral parts of the wall and being substantially uniformly spaced from the surface zone of the article, and the conductors comprising the central part of the wall of the inductor being smaller than conductors comprising a lateral part of the wall of the said inductor to provide less inducing current in the central part of the inductor than in the lateral part, and means for supplying periodically varying current to the inductor.

12. In apparatus for hardening a surface zone of a metallic article, a hollow inductor, the inductor having a chamber serving as a quenching fluid supply reservoir, a wall of the reservoir lying adjacent to the article and serving as means for carrying the inducing current, slots dividing the wall into a multiplicity of substantially parallel conductors, the conductors being of different sizes, the slots serving as passages to deliver substantially parallel sheets of quenching fiuid onto the aforesaid surface zone, and means for supplying periodically varying current to the conductors to induce heating current in the surface zone.

FRANCIS S. DENNEEN. WILLIAM C. DUNN. COURTNEY N. MITCHELL. 

